Steal strapping is perfectly matching strappings of very heavy, sharp-edged and/or hot packages.
The variety of types of steel strapping are the result of combining four basic product characteristics:
- Dimension: The wider and thicker the steel strapping, the greater the breaking load
- Corrosion protection
- Winding: ribbon or oscillated winding.
Packaging steel strapping is also called strap iron or simply steel strapping. There are numerous variations which can be arranged roughly according to the following criteria: Dimension, quality grade, winding and corrosion prevention. There is steel strapping in widths from 12.7 to 31.75 mm and thicknesses from 0.38 to 1.0 mm. The broader and thicker the tape, the higher is the tensile strength.
Another parameter influencing the tensile strength of the steel strapping is its "quality grade". A simple plain strapping can be distinguished from quality strapping and high-performance strapping. Plain steel strapping is a more or less untreated steel strapping, where the edges are deburred after rolling and cutting. The elongation level is at 3-6% and the tensile strength is about 700-800 N / mm². When steel strapping is treated further, it is called quality strapping. Here the edges are not only deburred, but also rounded. The elongation level is at 6-8% and the tensile strength is higher - approx. 850 N / mm². High-performance steel strapping shows the highest values with regard to elongation and tensile strength. Here the breaking elongation is at about 14% and the strength approx. 1,050 N / mm².
In the matter of rust protection three levels can be distinguished for quality-packaging steel strapping and high-performance strapping: blued, black-coated and zinc-coated. Blued steel strapping means that the strapping was heat-treated which protects against corrosion. Strapping on the other two protection levels is coated with a varnished layer. The black-coated steel strapping has a coverage of approx. 3 microns, the zinc-coated or galvanized strapping is covered with approx. 6 microns.
Finally, steel strapping differs in the type of winding - there are oscillated or ribbon coils. With the oscillated coils the strapping is wrapped in several layers. This means that a coil is about three times wider than the width of the steel strap itself. The dispenser carts for stack winding coils normally have a lid which one unscrews, sets the steel strapping then on an axis and shuts the lid again. The ribbon coils, also called disc winding strapping, is wrapped in single layers, so the ribbon coil is as wide as the steel strapping itself. In the dispenser cart for ribbon coils, the roll is simply put inside from the top; then the strapping can be unrolled with the help of a ball bearing.